University of Notre Dame synthesis of 2 d organic quasicrystals laboratory accident [introduction] quasicrystals have tease and attracted scientists for 30 years, and now this strange materials have a strange new members: formed from organic molecular self assembly of two dimensional quasicrystals.
quasicrystals have tease and attracted scientists for 30 years, and now this strange materials have a strange new members: formed from organic molecular self assembly of two dimensional quasicrystals.This peculiar quasicrystals was flat, consists of a single final ring molecules.Form groups within the molecule in this layer, like weak hydrogen bond to connect together.This in a group of strange way of assembly in this layer of other molecules formed a variety of shapes, including the pentagon, star, boat and diamond.If this is a rule of ancient crystals, so you might see these groups and shape in each layer in a predictable way appeared again and again.In quasicrystals, however, you can see in the same layer again and again the same shape, but it is not in an organized form.
Scientists say, leading to the quasi crystal and other crystal is the key to distinguish organic materials and self assembly of parts."It has significant difference with other crystals," physical chemist at the university of Notre Dame Alex Kandel says Alex Kandel, he accidentally found this material in laboratory, and the findings, published in the journal nature.Know most of quasicrystal is metal, and through the strong ionic bonds, rather than a weak hydrogen bonding closely linked, hydrogen bond in complex organic molecules, such as DNA.
As its name, as shown in the structure of quasicrystals is crystal part disorders.In other words, it is between the structure of repeat symmetric unit and complete disorder between the construction unit of the structure.Atomic unit in local is symmetrical, but on a larger scale is not regular repeat.Because these arrangement, quasicrystal is very smooth and is used for items such as titanium.
The first kind of quasicrystal is a materials scientist Daniel ShuXi terman (Daniel Schechtman) synthesis in laboratory accident in 1982, he won the Nobel Prize in 2011.Before that, scientists believed that half organization of quasicrystal structure is impossible.By now, we know that the opposite is true.Not only can quasicrystals synthesis in the laboratory, it also can be formed in nature.Princeton university in 2012 physicist Paul stein hart (Paul Steinhardt) shows the quasicrystal found in eastern Russia from falling into areas of meteorites.
Kandel's team surprises quasicrystals, when they actually is how want to study electronic distribution in the ferrocene formic acid, the latter is quasi crystal form of the original molecule.For such an experiment, the team needs to create a stable linear molecule group.However, scientists are trying to is the result of the accident has created two dimensional quasicrystals.
"The first picture really surprised us," said khander."Of course, to produce two-dimensional quasicrystal is not easy, that is why we are now seeing reports of quasicrystal is very limited, now from the first approval of crystal materials already has more than 30 years."
Germany by Martin Luther King, President of the university of Delaware, Wolf Widdra), suspicious of the latest study, he created the first 2 d quasicrystals and
in October 2013, reported the findings.He does not think there is enough evidence to prove that quasicrystal structure can appear in the area of large enough.
About the meaning of self assembly, many scientists are disputed.D Della thought this term can be applied to all of the crystal structure, but is not limited to this new discovery.Kandel debate said a structure composed of strong chemical bonds, as well as other quasicrystal - that is not self assembly.These powerful chemical bonds "overwhelmed" the individual building unit combined with the power of each other, makes the material had little choice but to form a group.In this new quasicrystals, the building unit is composed of weak hydrogen bond together."Self assembly is very interesting, because the power of the drive organization form is better than a single force structure formation to be more slim."Kandel said.